The present invention relates generally to instruments used during preparation of the ground surface of a site prior to building or landscaping. More specifically, the present invention relates to leveling instruments that can check elevation changes of a ground surface.
When a site is being prepared for a project, it is important that the ground surface be properly graded according to the designer""s specifications. For example, building sites must be properly graded to obtain the proper elevation of the building relative to the surrounding landscape, and landscaping sites (e.g., parks, golf courses, etc.) must be properly graded to ensure that certain aesthetic and drainage goals are achieved.
Grading projects are commonly started by surveying the site using a transit. During the surveying, markers are set into the ground to establish reference elevations. These reference markers are typically placed in a widely-spaced, grid-like pattern. The markers provide enough information to perform rough grading of the site.
An elevation map and hand level (sometimes referred to as an eyelevel) are then used to establish the proper elevation of the ground between the markers. The elevation map is used to determine the desired elevation of a chosen location. The actual elevation of that location is then determined in relation to one or more of the reference markers. More specifically, the worker will typically set a grading stake into the ground at the chosen location. A wooden rule is then unfolded, and one end of the wooden rule is rested on the ground with the wooden rule positioned vertically. Using the wooden rule as a vertical guide, the worker then uses a hand level to sight a nearby reference marker. The worker then approximates the position of the hand level on the wooden rule and uses this information to determine whether the chosen location is at the desired elevation. Any required change in elevation is marked on the grading stake. This process continues until enough locations have been staked to enable final grading of the entire site.
Because of the length of time and skill involved in using a transit to establish elevations, the number of reference markers established by the transit is typically maintained to a minimum by widely spacing them. The above-described grading stakes are then used to fill in the gaps. Although not as accurate as a transit, the use of a hand level and wooden rule to establish elevation is much quicker than a transit. This is important due to the large number of measurements that must be made on a typical site.
The present invention provides an improved apparatus for checking elevation between reference markers. The apparatus significantly reduces the amount of time required to establish the elevation of a location, and therefore can save considerable time in mapping desired elevation changes of a site.
The apparatus includes a measuring device (e.g., a tape measure) that can measure the distance from an elevated location to the ground immediately below the location. A sighting device and a leveling device (e.g., a hand level) are secured to the distance-measuring device so that a remote reference marker can be sighted. The distance-measuring device is calibrated such that it measures the distance from the ground to the centerline of the sighting device.